A double headed penis and a highly venomous spur. What you should probably know about the platypus

,So I wrote about the echidna in an earlier post and thought it only fair to write one for that other equally odd Australian monotreme – the platypus.  In case you’ve forgotten, monotremes are the egg laying mammals and there are only 3 species – 2 types of echidna and a single species of platypus found only in Australia.

platypus blog
Photo source: australiantraveller

This means that even though the platypus is often described as having a duck bill or a beaver tail its closest relative isn’t either of those. It’s the echidna! While not physically very similar looking, functionally they are. Both lay eggs, both have a single opening for all their waste stuff and sex stuff, both walk like reptiles (as explained in my echidna post), and both have multi-headed penises…

platypus penis
Photo source: CSIRO publishing

As you can see above, the platypus penis is quite specialised, and while its shape and structures are still not fully understood, scientists have noticed it nicely reflects what’s going on inside the female platypus.

The females have two ovaries but only the left is functional and produces eggs. In the platypus male the left head of the penis is the one that is larger and more exaggerated, supposedly helping to better target the egg producing ovary.

Platypus males have another secret weapon too, a highly potent venomous spur found on each of their hind legs. Venomous mammals are rare enough – beside the platypus there are just a few species of shrew that are as well, but the platypus is also the only known animal to exhibit temporally differential venom production. So basically producing venom differently at different times of the year.

In the spring breeding season the male’s venom glands swell and produce more venom, and you definitely don’t want to receive a dose of it. In humans it causes instant and excruciating pain that can’t be relieved by morphine and other first aid methods. One man who was jabbed on the finger had pain in the area up to four months later.

So despite its adorable odd-ball appearance, the platypus really packs a punch. Who would have thought the combination of a duck bill and beaver tail could prove so successful? The platypus really is one unusual animal.

Photo: View of a platypus from above
Photo: Nicole Duplaix

Screen Shot 2016-07-17 at 6.26.54 pmReferences 

Callaway, E. (2010). Poisonous platypuses confirm convergent evolution. Retrieved October 6, 2013, from: http://www.nature.com/news/2010/101012/full/news.2010.534.html?s=news_rss

Dufton, M. (1992). Venomous mammals. Pharmacology and Therapeutics, 53(2), 199-215. Retrieved via Science Direct.


  1. Interesting blog! Especially to a biologist like myself. I never saw a platypus in the wild, but I once had an echidna nearly walk on my shoes while I was hiking in Lamington National Forest, near the Gold Coast.


    • Thanks! I’m studying zoology so it’s all the things i’m interested in too 🙂
      I’ve only see echidnas as well, but not one as close as you in the wild! I have however patted the stomach of a domestic one, super adorable.
      What’re you researching at the moment – if you don’t mind me asking?


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